Kaiba Conversion
by KaibaGirl007
Summary: A mysterious room buried deep beneath the Kaiba Corp building sends Mokuba and the Doctor on an adventure that will reveal dark and hidden secrets. - Part one of the 'Doctoring The Blue Eyes' trilogy.
1. Chapter 1

**This is a Yugioh and Doctor Who crossover fic, and I own no rights to either of them.**

**Set sometime after the anime in the Yugioh timescale. **

**The Doctor featured is the tenth one (David Tennant), set sometime after Rose but before Martha in the Doctor Who timescale.**

**Chapter One**

It was a day just like any other in the city of Domino. The streets were filled with people as they raced to their destinations during the morning rush hour, roads were clogged with traffic and sidewalks crowded with pedestrians. Outside the Kaiba Corp building people were so caught up with other things that nobody heard the distinguishing sound of the TARDIS as it appeared out of thin air right beside the bushes next to the building.

The pulsing, whining and whirling noises of the TARDIS stopped and the doors to the nineteen fifty's London police call box opened. The Doctor stepped out from his time machine with his brown trench coat trailing behind, as he looked around the setting what lay before him. "Let's see what we have here." He smiled to himself as he approached the three stone Blue Eyes White Dragons that stood guard outside of the entrance in to the KC building.

Inside the building the Doctor walked straight past the reception desk as he headed for the elevator to take him up to the main control room right on the top floor. "Sir, may I see your ID please?" The receptionist shouted after him as she struggled to do her own job and that of the security guard who had been fired the previous day.

"Sure." The Doctor smiled as he doubled back and opened his ID wallet to show the receptionist.

"Your first day on the job, eh?" The receptionist asked seeing that the wallet in front of her identified the man as one of her boss' new researchers.

"Is it that obvious?" The Doctor laughed nervously as he placed his ID back into his coat pocket and made a mental note to try and blend in a bit better.

"I would have remembered someone as good looking as you." The receptionist flashed a flirty smile the Doctor's way and added to warn him. "Mister Kaiba doesn't tolerate lateness."

The Doctor smiled and nodded in return before heading for the elevator once again. He rode it all the way up to the top of the building and exited to follow a corridor round to the huge control room where researchers were busy typing away at their work stations. It had been a while since he had seen technology this advance during the time period he was currently visiting.

"Hey you, let's see some ID!" Mokuba ordered when he spotted the newcomer enter into the room. The Doctor complied and handed his ID wallet to the shorter scruffy-hair boy who quickly handed it back to him, satisfied that the unfamiliar man had permission to be there. "Okay, but next time don't be late, my brother isn't as forgiving as I am."

There was an empty work station across at the far end of the room which was perfect for the Doctor to use as it was almost hidden out of sight from the rest of the room. He made his way over and began to randomly press the keyboard, making it look like he was busy working.

After hearing his brother address the latecomer Kaiba had been stood watching the whole time. Still focusing his gaze on the brown coated man he made his way across to Mokuba. "That guy you just let in, who is he?" he asked.

"One of your researchers." Mokuba replied as he glanced up to his older brother in some slight confusion.

"I choose all of my researchers myself, and he isn't one of them." Kaiba told his brother as he watched the impostor through narrowed eyes. He glanced down at Mokuba who should have known better than to let a complete stranger in his research lab. "Keep an eye on him; we'll soon see what he's up to." He flashed one last glare across the room before he left for his office.

Mokuba could sense that his brother was annoyed with him and didn't want to displease him again. Slowly he moved from work station to work station, keeping a close eye on the impostor who had snuck his way into the building. He wasn't going to let his brother down and would do what it took to keep track of him.

When no one was looking, the Doctor took out a small silver device and pointed it directly at the work station in front of him. Almost instantly every file stored on the Kaiba Corp system, regardless of security measures, was displayed before him in a blur as each flashed on screen for a brief moment. The doctor frowned as the last file disappeared from the screen now leaving it blank. He had been able to read through each file for the short time that they had been displayed and couldn't see any reason as to why the TARDIS had dragged him to that location. Sure the technology that the company was using was advanced for it's time, but there was nothing _'alien'_ detected within the system. He placed his small device back into his pocket and left to consult with the TARDIS' controls on the situation.

The Doctor made his way back along the corridor to the elevator and was about to ride it down when he heard the voice of the scruffy haired boy call out for him to 'hold' the elevator for him. Not wanting to stand out and draw more attention to himself he did what he thought any other human would do and stopped the doors from closing so that the boy running towards him could enter.

"Thanks." Mokuba panted as he stood beside the Doctor and tried to get his breath back after having sprinted so as not to fail his brother's orders of keeping an eye on the stranger. He watched as the doors began to close but were stopped again, this time by a hand that he knew belonged to his brother, and Kaiba too joined them.

"Have you seen my brother yet?" Mokuba nervously asked the Doctor as Kaiba proceeded silently to the back of the elevator. The doors closed and the elevator began to descend the shaft.

"No, not yet." The Doctor replied politely to the boy's question, clearly unaware that the CEO in question was stood directly behind him.

"He's been dying to meet you." Kaiba heard his brother say as he glared at the back of the man's head and wondered who would be dumb enough to try and sabotage his company without doing research into the identity of who owned it?

The Doctor just smiled in response but didn't say anything more on the subject causing the elevator to fall silent before Mokuba broke it: "I saw you downloading information from the company's database."

Kaiba's eyes widened from hearing Mokuba's comment. He had the best security systems that had ever been created, there couldn't have been anyway that someone could just access the data unless they had gone to great lengths to figure out a way to bypass them. Letting his anger take control he forced the impostor tightly up against the wall and stared down at his little brother with annoyance in his voice. "Why didn't you mention that fact sooner?!"

"Seto, calm down!" Mokuba cried, not paying attention to the tone his brother had used towards him, as he feared for the stranger's safety from the force his brother had used to restrain him. "We're in an elevator, he's not going anywhere." He pulled at his brother's arms but still they remained strong.

"Let me guess, your brother right?" The Doctor wheezed in a rather cheery voice as he looked down at Mokuba, a smile still present on his face despite being pinned tightly against the wall by the CEO.

Mokuba nodded as he still tugged at Kaiba's arms and managed to relax his brother's grip so that the man could now breathe again.

"I want answers and I want them now!" Kaiba demanded. "Who sent you? Was it Pegasus? Siegfried? Dartz?" he reeled off the names of those who had tried to take over his company in the past.

"I have no idea who any of those people are." The Doctor answered truthfully shaking his head and still smiling.

Kaiba was losing patience with the smug stranger. "Who are you?" he growled.

"If you'd like to take a look at my ID." The Doctor carefully attempted to reach for his coat pocket, the move was allowed by Kaiba although he watched the man for any sudden movements he may attempt to make. Taking his wallet out, the doctor handed it over to the CEO.

"It's just a blank piece of paper." Kaiba growled in annoyance at what he had been shown to him and snatched the wallet from the Doctor's hand.

"No it's not." Mokuba looked puzzled as he took the Doctor's ID from his brother's hands and looked at it to see the same details he had seen earlier. How could he have not seen that it clearly stated that the man's name was John Smith? Mokuba stared hard to try and understand what it might have been that made is brother believe that the ID was fake when slowly the details disappeared and left just a blank space where they had once been. "How'd it do that?!" he asked in surprise.

"I'm impressed." The Doctor beamed a smile at Kaiba and ignoring Mokuba's question. He lifted his arms to try and prise Kaiba's from his own. "Very few people can see psychic paper for what it is unless they've been told."

"You're avoiding my question." Kaiba snapped as he shook off the man's arms from his own.

"I'm the Doctor." Came a cheery reply only to be met with silence from the two brothers. "A Time-lord." He added.

"Doctor who and a what?" Mokuba asked, his face wrinkled up in confusion as he handed back the ID wallet to its owner.

"Just 'The Doctor'" he smiled glancing down at the younger brother who seemed more interested than the older of the two. "I travel through time stopping at intervals to take in the sights."

Kaiba rolled his eyes not amused at what was being said. "Cut the crap." He slammed the Doctor hard against the wall hoping that the violence may loosen the man's tongue.

The lights flickered from the sudden force of impact and the elevator slowly came to a halt as it gradually lost power. "That's one nasty temper you have there." The Doctor laughed.

Mokuba typed in several code combinations on the elevator's control panel but nothing happened. "Aw, great! Now we're stuck here." He looked up at his brother. "Nice going, Seto."

Kaiba glared back at his brother after the sarcastic remark and the Doctor took the opportunity to slip free from his grasp at the slight distraction. "I can get us moving again." He announced as he made his way over to the control panel. "And for your information, I wasn't downloading anything."

"And you expect me to believe that?" Kaiba growled, baffled by how the man had escaped from his grasp so easily.

"Believe it or not, it's the truth." The Doctor sighed as he reached into his coat pocket again to produce the thin, metal cylinder, pen like object that Mokuba had seen him using earlier. "I was just looking for something."

"Looking for what?" Kaiba demanded.

"I don't know, I didn't find it." The Doctor shrugged as a small light flashed from the device he held in front of the elevator's controls.

"Just what is that thing?" Mokuba asked curiously.

"My sonic screwdriver." The Doctor replied proudly to the boy who seemed to be taking a real interest in everything he had told him. "It has many uses; it can open virtually any lock, mechanical or electrical device, repair equipment, be used as an offensive weapon – although it can't kill anyone, - and it can even take out screws." He said all of this in one go before the panel fell away from the wall to reveal a network of criss-crossing wires and several hidden buttons.

Again, Kaiba rolled his eyes at the nonsense that was leaving the Doctor's mouth. His brother may have been easily fooled in to thinking that the strange device was some kind of super multi purpose tool that could only exist in science fiction, but he wasn't. It was clear to him that the device was nothing more than a simple electric screwdriver and its owner a crazed lunatic.

"Does this building have a room below basement level?" the Doctor shouted over his shoulder at Kaiba whilst he gently trailed his fingers over the buttons and rested upon one which had been completely disconnected from the circuitry board.

"No. Why?" Kaiba asked suspiciously.

"I think that I've just found what I was looking for." The Doctor smiled as he pointed the sonic screwdriver at the exposed wires and a flash of light erupted out of the end of the device causing the lonely button to become hooked up to the board and full power to be regained. He pressed the button sending the elevator to descend to its new destination.


	2. Chapter 2

**Big thank yous for the reviews :) **

**Chapter Two**

The elevator had continued down the shaft, passed the basement and now came to a stop in a room located far below Kaiba Corp. Some dust fell as the doors pulled apart so that the three passengers could alight into the unknown.

Down in the massive space before them they could see what looked like a huge production line of some sort. The machinery had several large circular chambers, each of them with a conveyor belt leading into each one, which then connected to an even bigger final chamber.

"Whoa!" Mokuba voiced what they were all thinking.

"And you had no idea that this was here?" the Doctor asked looking over his shoulder towards Kaiba.

Kaiba shook his head still shocked with amazement that this room had been under his company's building the whole time without him knowing. "None whatsoever."

"I'm going to go and check this thing out." The Doctor declared holding his sonic screwdriver at the ready. As he was about to step forward he felt himself pushed aside as the two brothers passed by him. "You two can come too, but no touching." He shouted mockingly behind them.

"Joking or not, _nobody_ tells me what to do!" Kaiba snapped as he spun around to face the Doctor who remained just outside of the elevator. "Especially not on _my_ own property." He glared loathingly as the brown coated man mimed pulling a zip across his lips.

"Seems like you've already been put through one of these." The Doctor muttered to himself commenting on the CEO's lack of humour as he watched Kaiba continue down some steps which lead further into the room full of machinery. He followed on behind with all signs of his pervious cheery self absent.

The brothers had stopped next to one of the conveyor belts to see that spaced out along it, about six feet apart, many large mechanical arms that were fixed to the belt. The purpose of what the lines did was completely unknown to them. Mokuba leaned closer to get a better look and jumped as he felt his brother's arm pull him back. He watched Kaiba shake his head disapprovingly before he strode off to look at the rest of the set up. Mokuba turned his attention back to the conveyor belt as the Doctor passed by him.

Unlike the two boys, the Doctor knew what the machine's purpose was as he had seen many during his life. Although it was a slightly different design the output would always be the same, and because of that he had to make sure that it would never be activated. His head turned as he searched for the main control unit but couldn't find any obvious sign of it, and then he heard the younger brother cry out from where he had passed by him.

Mokuba was now standing on the conveyor belt after having been suddenly pulled onto it by one of the attached arms. "I didn't touch anything!" he shouted in a panicky voice as both his brother and the Doctor turned their attention to him. The belt began to move towards one of the circular chambers and Mokuba had to regain his footing as he swaggered from the start up motion. "Seto, help!"

Within just a couple of seconds Kaiba had leapt up onto the belt and was now by his brother's side. He took hold of the restraining arm with both of his hands and pulled with all his might. "I'll soon have this thing off you." He assured his little brother as he started to kick at the arm's base.

"I'm going to deactivate it." The Doctor shouted across to the two brothers, neither of them seemed to have heard him. Franticly he searched the biggest of the chambers but still hadn't found what he was searching for. He then spotted some footholds leading up to the top of the main chamber and quickly climbed them to find the controls.

Kneeling beside the controls, the Doctor pointed his sonic screwdriver at them. The end of the device began to glow and several sparks flew out from it before it died out. "Now's not the time to start acting up." He hissed hitting the device against the palm of his hand and turned to look for the brothers only to see them disappear into one of the chambers as the doors closed behind them, sealing them inside.

There was no time to waste, the Doctor had to disable the thing before……. His eyes widened as he saw lights flashing and whirling above the chamber that the two brothers had entered. "No." he gasped as he tried his sonic screwdriver again, but still it refused to work.

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Just seconds before they had entered the chamber, Kaiba had managed to break the casing away from the bottom of the mechanical arm which then left a web of wires exposed. He smashed his foot down one last time which ripped through several of the wires causing the arm to release its grip on Mokuba, but it had come too late as the two brothers now found themselves locked inside the circular chamber.

Inside the chamber was dark with a dim glow coming from beneath them. Kaiba looked around finding it hard to take in their new surroundings through the darkness but could just make out the silhouettes of more restraining arms that lined the edges of the chamber, and figured that it must be some kind of holding area, but for what? He walked back along the conveyor belt to the closed doorway they had entered and tried to prise the doors open with his bare hands.

"What do you think it is that this machine does?" Mokuba asked rubbing his wrists, a hint of fear in his voice which had been brought on by the darkness around him.

"I don't know." Kaiba replied as he struggled to get the doors to move apart. Reluctantly admitting defeat, he slammed his fist against the cold steal before stepping back to beside his brother.

The sound echoed throughout the chamber before it died leaving only the sound of Mokuba's racing heart to pulse in the eerie stillness. Though he was scared by the dark, Mokuba was relieved that his brother wouldn't be able to see the look of fear upon his face. He wondered how his brother managed to stay so calm at a time like this but his thoughts were soon interrupted as a whirling sound surrounded them and he was pushed to the floor where he landed on all fours.

Mokuba quickly scrambled round to a sitting position and in the tiny bit of light from below he could see his brother dimly lit as he struggled to break free from several of the mechanical arms. Kaiba had pushed his little brother out of the arms reach just in time and instead found himself now being restrained. "Seto!" Mokuba cried as he was about to get to his feet.

"Don't move!" Kaiba barked, and saw the shadowy figure of his brother stop at his command. He pulled at the arms again but it was no use, they were too overpowering for him and stopped his struggling as the belt began to carry him away from Mokuba. His brother was safe from harm and he wanted it to remain that way. "Stay as far away from these things as you can." He told him through the gloomy darkness.

His heart racing and not moving from where he sat Mokuba nodded in reply to what his brother had told him. "What about you?" he cried in concern.

Kaiba had no time to answer and give false reassurance to his brother as he was taken through another set of doors which closed swiftly behind him. More restraints sprang towards him as they guided the CEO across the new chamber and led him to a huge steal plate that they tightly secured his body too. Again he struggled to try and break free, but still it was no use and felt his head drawn back as it too was clamped into place forcing him to glance upwards at a small orb which dropped down from the ceiling above him.

Light danced from the orb as it slowly lowered itself and stopped hovering just centimetres above Kaiba's face. Until now he had remained calm, but as the orb stopped he saw several spikes and blades protrude from the metallic sphere and felt fear grip at his heart.

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Mokuba remained down on the floor as Kaiba had instructed him to do so and felt like his heart was about to explode from his chest any moment now. He was extremely scared at not being able to see or hear anything and wished that he had been able to do something to stop his brother from being taken from him. Why did he always have to be so helpless all of the time? Surely there was something he could have done to help his brother? He scrunched his eyes closed as he hated himself for being so weak and then heard the most terrifying sound he had ever heard in his life as Kaiba screamed out only to be silenced a split second later.

"Seto!" Mokuba cried out as he forced himself up and blindly ran over to the direction which he had seen his brother taken just moments before. He ran straight into the steal door and pummelled at it with tears running down his face as he cried his brother's name over and over again. Behind him the other door hissed as it slowly opened and he saw the Doctor standing there in the light which flooded into the chamber. "Help me!" he pleaded, desperate to get through the door.

The Doctor approached Mokuba at a speedy pace and gently eased him away from the door. "Stand back." He told the boy as he ran his device over the edge of the doorway trying to unlock the mechanism to no avail. He tried again but still nothing so he turned to exit the chamber clearly upsetting the frightened boy even more. "I'm going to try and find another way in." he explained so that Mokuba knew he hadn't given up trying to rescue Kaiba though he feared he may be too late.

Quickly the Doctor raced around to the back of the main chamber and waved his sonic screwdriver over the doorway which opened instantly. He hesitated for a moment as he thought about the danger he may be walking into but still continued to step inside for his search for the older brother.

An eerie mist filled the chamber making it hard for the Doctor to see too far in front of him. He slowly wadded his way through the mist as he headed for the area Kaiba had been taken to and then froze as soon as he started to make out a figure stood before him. The sonic screwdriver was immediately raised as the Doctor continued to take further steps towards the figure which hadn't moved an inch.

The blood in his veins turned to ice as the Doctor could now properly see the face of the humanoid robot before him. At about seven foot tall the cold, steal weapon of destruction looked down at the approaching man, The whole purpose of the machine had been to churn out robots like this which the Doctor knew as Cybermen. With its chest panel exposed; a sign that the conversion had not been completed, the Cyberman didn't show any indication of life or movement.

As he lowered his device, the Doctor nervously laughed at his own stupidity of being startled so easily, but then again his past experiences gave him every right to be wary. He stared deep into the black empty eye sockets; each of them had a groove which could be mistaken as a teardrop, as he squeezed by to carry on his search.

Around the next corner the mist began to disappear and the Doctor could now see droplets of splattered blood on the floor. He edged closer and a pair of legs came into view, half cover by a blood stained white coat. The amount of blood that could now be seen as the Doctor's gaze moved further up Kaiba's torso told him he had been too late to save the boy. He turned away as he saw fragments of Kaiba's head scattered over his chest and knew that the image of the headless body would haunt him forever as it added to the hundreds of thousands of people that he'd seen die during his lifetime.

Much quicker than what he had entered, the Doctor backed out of the chamber, his wrist held up across his nose and mouth as he felt slightly ill; whether it was the stench of blood from the body's remains or the fact that he now had to break the news to the younger one, he wasn't sure. He saw Mokuba gingerly approaching the doorway, his face all red and damp with tears, wanting to know what had become of his brother. "I'm sorry. He's dead." The Doctor spoke quietly.

"Nooooo!" Mokuba wailed at hearing the news and tried to push past the Doctor to get to his brother.

"You don't want to go back there." The Doctor insisted as he caught Mokuba and forced him as far back from the chamber's entrance as he could. The boy was surprisingly strong using all his emotions to do whatever it took to be reunited with his brother, but still the Doctor couldn't allow him to see the horrible sight. "Just remember him the way he was."

"Seto." Mokuba sobbed as he collapsed in a heap at the Doctor's feet. Just how was he supposed to remember his brother, as the cold hearted person he had become or as the warm, loving boy before their stepfather had changed him? Mokuba clutched at his locket knowing which he preferred and now would never be able to see again. "How did he die?" He glanced up at the Doctor with teary eyes.

"This machine is a conversion unit for Cybermen." The Doctor began to explain but he would spare going into all the finer gory details. "It takes humans, removes their central nervous systems and transfers them into robotic bodies to create the ultimate killing machines." The remorse from not being able to prevent the unnecessary death ran deep within his heart, the only comfort from the whole thing was that the machine would not be able to be used again. "Fortunately, this time the process was not completed."

"Fortunately?!" Mokuba's voice was beyond angry. "Seto is dead and all you can say is 'fortunately'?"

"If the process had been completed then it is possible that neither of us would be here right now and many more people would suffer the same fate as your brother." The Doctor's voice was firm with his explanation yet understanding of the boy's outrage towards him. "I am truly sorry about your brother."

"Now I really am alone." Mokuba lost himself in his own thoughts. Kaiba had been his only family and although he knew that his brother had loved him it was hardly ever shown, which often left him feeling isolated in his own life. He looked up at the Doctor. "Do you have any idea how that feels?"

The Doctor knew the feeling all too well and knew that the boy would never be able to understand the loneliness that he had experienced. "Yes." He replied sadly closing his eyes and hanging his head.

"Liar!" Mokuba roared in anger, the man couldn't possibly understand what he had just lost.

Not saying a word, the Doctor let Mokuba continue to yell at him. Soon all of the boy's anger would be out of his system which would then allow him to grieve the loss of his brother once he himself had moved on to his next destination in time. First he'd have to re-search to make sure that no details of this alien technology remained to be used again and then……

_Thump! Thump! Thump!_

The Doctor's eyes sprang open as he heard the chilling sound come from the chamber behind them. "Get up and follow me." He told Mokuba who too had fallen silent at hearing the noise.

"_Delete." _

"Now!" the Doctor shouted his order and grabbed the boy as he dragged him at a fast pace towards the elevator. Only once they had reached the top of the small flight of stairs did he let go to turn around and view the Cyberman that was still coming after them. He cursed himself again for being too slow at destroying the machine as it had managed to create a successful output after all.

"Seto?" Mokuba looked at the large metallic figure that came thumping closer to them, wires where visible in its chest area and it looked as though it was sad from the dark teardrop like eyes.

"_Delete" _The robotic voice repeated as it focused on its targets across the room.

"The conversion was complete." The Doctor mumbled is thoughts as he reached into his coat pocket for his sonic screwdriver. It may not be able to end the life of a living being, but the Cyberman was mainly machine so once the exposed wires were disconnected it would be disabled and then the still living organ inside the metal casing would be allowed to rest. "I'll end this quickly."

"No." Mokuba took hold of the Doctor's device and fought to keep it turned away from the approaching robot as he was unable to snatch it from its owner's hand. "He's my brother."

"_It's_ a killing machine." The Doctor argued.

"I can reprogram him." Mokuba explained. If there was a chance that he could still have his brother, even as a robot, he wasn't going to let that be taken away from him. "He's the only person I have in the whole world; please don't take him from me."

"_Delete." _The Cyberman had now reached the stairs and was about to ascend them.

How could he make the boy understand that his brother was gone? Soon the Cyberman would be right on top of them and then it would be too late to save themselves. The Doctor stared into Mokuba's pleading grey-blue eyes. "Everything that made your brother 'human' died the moment they smashed open his face to get at his brain. You won't be able to get him back this way."

Mokuba's mind now reeled with the horrible image of his brother's smashed up face, he hadn't seen the body but now knowing what had been done to Kaiba he had began to accept that his brother would never be returned to him. He let go of the doctor's hand allowing him to carry on and deactivate the Cyberman who was almost a few feet away from them.

A blue spark flew out from the end of the sonic screwdriver, ripped through the exposed wires and brought the Cyberman to a stand still, its arms reaching forward for them. The Doctor let out a deep sigh of relief and brushed the sweat from his forehead. He looked down to where Mokuba was crying beside him. "Come with me."


	3. Chapter 3

**Whoa, this fic seems to be received quite well. Thank you for the reviews left. :)**

**I hope that you continue to enjoy it and that I don't disappoint any of you.**

**Chapter Three**

_Ping!_ Sounded the elevator as the doors opened up to the ground floor of the KC building and there stood the Doctor with Mokuba by his side. Taking one last glance to make sure that the control panel had been replaced completely the two of them began to walk towards the exit with the Doctor leading as Mokuba quietly followed along behind hanging his head low so that nobody would be able to see his face.

"Where are you taking me?" Mokuba asked once they were outside as they passed by the three stone dragons.

"You'll see soon enough." The Doctor replied as he looked around for the big blue phone box and headed over towards it pushing open the doors to let them enter. He watched as the boy briefly glanced around the TARDIS but didn't say a word in response to what he saw. "Aren't you going to comment on how big it is in here compared to the size of what you saw outside?" he laughed as everyone else he had ever shown had been taken by surprise at that the first time they witnessed it, and saw Mokuba glare up through his black hair at him. "Guess not." He muttered under his breath.

Mokuba looked at he man who didn't seem to be taking things seriously. "My brother just died and you want me to just forget about it?"

"Yes!" the Doctor exclaimed a little too excitedly.

"What!" Mokuba was horrified.

"Oh wait, that didn't come across quite as well as I hoped." The Doctor frowned knowing that he was getting ahead of himself and not fully explaining things through properly which he had a habit of doing a lot. He crouched down so that he was on a move even eye level with Mokuba. "Destroying that machine wasn't enough, I still need to find out how the information for that technology came about and get rid of it. My best chance of doing that would be going back to when the building was first built and destroying all traces there and then, that way none of this would have happened just now."

If what the Doctor was saying was true then his brother would still be alive and neither of them would have any other knowledge of what had happen, so he'd be able to forget about the whole thing and move on. There was just one problem though; "There's no such thing as time travel, it's not possible." Mokuba stared coldly at the Doctor for trying to get his hopes up when he was most vulnerable. Kaiba had always found a scientific explanation for everything and it was only now that he wasn't here that Mokuba believed the words which had shattered many of his fantasies.

"That's your brother talking." The Doctor smiled sadly, he knew that Mokuba believed as he had been so open-minded and paid a keen interest in what he had said in the elevator on the way down to the hidden room. He held his hand out in front of him as though holding something with his palm faced up. "You see time; it's like a big ball." He flexed his fingers squeezing the air and then decided that explaining wasn't going to do the trick this time, the best way would just be to show the boy.

Mokuba winced as the Doctor suddenly grabbed hold of his bruised wrist and lead him to the centre of the room where a huge workstation stood at the centre "These are the TARDIS' controls. You enter your time, date and destination here, here and here. Then you pull this lever which will send us there." He heard the Doctor explain as he pointed to several parts of the surface area that they stood in front of.

The Doctor looked down at the boy who hesitated for a moment. "Just don't choose anywhere that we may run into yourself as that would lead us into a whole heap of trouble." He said as he turned to give Mokuba some privacy over the destination and felt the TARDIS shudder slightly as it took them both through time and space and stopped shortly afterwards. "Well shall we have a look outside?" he asked, smile on his face and eyebrows raised.

Outside of the TARDIS the location had changed. Instead of being right outside of Kaiba Corp in Domino like they had been just a few minutes ago, they were now placed at a tourist spot that over looked ….

"New York!" The Doctor beamed a smile at Mokuba. "Good choice." The boy had to believe now, there was no other way he would be able to explain what he saw.

Mokuba glanced out across his chosen destination, the skyline of the city still had the twin towers of the World's Trade Centre and the streets below were filled with people going about their everyday lives. "Its beautiful." He whispered with a smile of mixed emotions and his eyes filling up as he thought about his brother.

All the times Kaiba had assured him that everything could be explained with science and what couldn't was just pure fantasy made Mokuba think of other things that his brother had ever told him. He had always believed every single word that his brother spoke but now they seemed like lies as his explanations had been proven wrong. So what else had he been lied to about?

Had they _really_ been placed in the orphanage because both of their parents had died, or dumped because they had been unwanted children the whole time? He couldn't remember much about their father and nothing of their mother, so now it seemed plausible. And what about Gozaburo? On a couple of _very_ rare occasions Kaiba had said that he had been a victim of their stepfather's abuse,- avoiding all further details of course,- but apart from seeing his brother pushed to excel with his schoolwork, Mokuba had never witnessed or experienced any himself. And was his brother innocent over the old man's death? Kaiba had always pleaded not guilty to the murder speculations that surrounded Gozaburo's death, which in the end had been declared a suicide due to lack of evidence to prove otherwise.

Before he had the chance to ponder over anything else that he had been told which might turn out to be untrue, Mokuba shook the previous thoughts from his mind. It didn't matter anyway as he loved his brother regardless of what he had or hadn't done and was just glad to be able to have the chance of getting him back.

With his arms crossed resting on the rail that surrounded the viewpoint he rest his head on them as he gazed out over the city. "I'd sit for hours in my brother's office looking out of the windows, just to be able to be close to him." Mokuba confessed.

Standing next to Mokuba, the Doctor too leaned on the rails and admired the city. He couldn't stop himself from letting his thoughts wander to his last assistant and wondered if she'd ever be able to forgive him for what he'd done to her? A dark looming shadow on the horizon broke him from his thought. "Just out of curiosity, what was the date you chose?" he asked the boy beside him.

"Hmm?" Mokuba hadn't been paying attention to the Doctor's question but followed his gaze till he too saw the approaching airplane. His eyes widened at the foolish mistake he had made when entering the information to the TARDIS' controls. Picking the first date at random and thanks to his brother's words he hadn't expected it to work at all, but now Mokuba regretted typing the destination. "I want to leave." He looked up and told the Doctor.

The Doctor nodded in agreement, what was about to follow was shocking and disturbing enough the first time around without have to witness it a second time and up close. Together they fast tracked back to the TARDIS and as they entered inside heard the screams and cries from the people gathered on the tourist point as the plane hit the north tower.

Closing the doors behind them the Doctor remained where he was as he watched Mokuba stagger down the steps and stumble to fall and land on his knees. "That was very foolish." He said disapprovingly as he slowly made his way down the steps, a hand held out to help Mokuba back to his feet but simply ignored by the boy, or possibly just not seen, the Doctor wasn't sure which.

"I wasn't thinking." Mokuba cried as he closed his eyes trying to block out the thoughts of what was unfolding outside behind them. Hundreds of people would now be loosing their lives and thousands more affected in its aftermath. Then an idea came to him; "We have to go back." He told the Doctor as he pushed himself up.

"Pardon?!" the Doctor exclaimed as he ran after the boy who was now almost at the TARDIS' controls.

"We can go back and stop it from happening." Mokuba started typing on the panel. "An hour or two should be enough time to warn and evacuated people before ….. Ow!" he cried as the Doctor took firm hold of his injured wrist, stopping him from entering the data.

"No." the Doctor said firmly.

"But we can help them." Mokuba protested as he tried to pull away only causing the Doctor to tighten his grip. He watched as the Doctor silently shook his head. "Why won't you help those people yet you're willing to help me? Isn't saving hundreds of lives more important than just one? Do you get a thrill out of deciding who lives and who dies?"

"No, I don't get a _'thrill'_ or _'decide'_." The Doctor replied angrily at Mokuba's choice of words. "The difference is that their death is natural and your brother's wasn't."

"Natural?!" Mokuba raised his voice. "You call terrorists crashing airplanes into buildings natural?!" he couldn't believe how heartless the man was being and pulled to try and free himself once more. "Please let go, you're hurting me." He begged with teary eyes.

The Doctor looked at his hand gripped around the boy's. He hadn't meant to grip so tight and released his hold so that Mokuba could massage the area with his other hand. "Humans have always fought throughout history and sadly will continue to do so; this tragic attack on innocent lives is just another example." He sighed feeling the boy's frustration of having the power to intervene but doing nothing about it. "I can't go interfering with events of the past just because something terrible happened, if I did then I'd been changing the history which follows after. As a Time-lord, I've taken it upon myself to track down those rouge travellers who try to alter events to their favour and stop them from doing so, then at other times I just like to sit back and view history. All the time I interact as little as possible and go unnoticed, but earlier today my interference cost your brother his life. Because of me he died, and that is why I'm going to right it as otherwise it wouldn't have happened."

Mokuba listened carefully to what the Doctor had to say. He hadn't thought about anything like that on a wider scale, all that had filled his mind had been the lives of those people who had died from the attack. "Do you ever want to intervene?" he asked the Doctor.

"Lots of times." The Doctor nodded sadly. He had learnt to resist temptation as he now knew the consequences for interfering. Not wanting to have the chance to dwell on the thoughts of his past he changed the subject back to their task. "So, just when was the KC building constructed?"

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"Looks like you were wrong." The Doctor said to Mokuba as he poked his head out of the TARDIS and looked towards the KC building which stood high and proud towering over the rest of the city.

"But Seto said that the building was only a decade old." Mokuba exclaimed as he'd been expecting to find the building partly finished once they had travelled back the ten years.

"Doesn't matter." The Doctor assured. "We'll destroy the machine here and now, and if I can't find the information I need then I'll just return you to your time and continue further back on my own until I do."

They left the TARDIS and walked out across the blank empty space, where Kaiba would later build the three Blue Eyes statues, towards the building and entered. "Sir, can I see your ID?" Security demanded as a man stopped them both.

"Sure, not a problem." The Doctor said taking out his psychic paper to show the man and flashed a smile towards Mokuba who looked slightly worried.

The security guard glanced from the wallet to the Doctor, back to the wallet and then at Mokuba who smiled nervously as the man's eyes narrowed on him. "Okay you may proceed." He said and handed the psychic paper back to the Doctor.

"That was a close one." Mokuba sighed as the two entered into the elevator.

"Nah, psychic paper hardly ever fails, only the _extremely_ smart or _extremely_ stupid can see that it's blank." The Doctor took out his sonic screwdriver and started to remove the panel from the controls to be able to get at the hidden button underneath. "I must remember to recharge this thing." He said as he struggled to get it to work properly.

_I wonder which Seto is? _Mokuba thought to himself after hearing the Doctor's remark about being able to notice the psychic paper. _Extremely smart or extremely stupid? That's easy he's extremely smart, but then again he didn't believe it possible to time travel. But he can wipe the floor with me at chess, yet he sucks at playing….._

"No!" the Doctor shouted with frustration and snapped Mokuba out of his thoughts. "Who in their right mind would go to the extra trouble of building a hidden underground room of that size _after _the main building has been completed?!"

"It's not there?" Mokuba asked in disbelief.

"We're going to have to go forward again." The Doctor was busy placing the panel back into place. "Say five years maybe and see where that brings us."

"Seto took over the company five years ago, so you should find it sometime between now and then." Mokuba pointed out.

"True, but I like five; it's a nice even number." The Doctor smiled as the doors opened and they stepped out to leave the building with Mokuba glancing up at him worryingly as though he had said something stupid to the boy.

They passed by the security guard and began to make their way down the steps when Mokuba suddenly hid behind the Doctor using the brown trench coat to hide himself from view. "What is it?" the Doctor asked him.

"My step-father." Mokuba whispered as he peeked out from behind the coat to see Gozaburo Kaiba coming up the steps towards them and then also noticed a ten year old Noah followed along behind him.

"But I don't want to learn how to run the company; I want to _play_ with my friends after school." Noah whined dragging his feet as he followed his father. "Why won't you let me be like any other kid my own age?"

"Don't be a slacker." Gozaburo answered not wanting to get into an argument with his son out in public. "You're lazy and lack motivation." He shouted behind and then glared at the Doctor as he passed by him before entering his building.

"I'm _not_ lazy, and I _don't_ lack motivation." Noah grumbled to himself tired of always being put down by his father. He noticed the Doctor's coat move and caught a brief glimpse of a boy hiding beneath it. "Would you like to play with me?" he asked in a happier tone.

"He's shy." The Doctor told the green haired boy who looked saddened by the news and then jumped to hurry up following his father as his name was yelled out angrily. "I thought you only had the one brother?" the Doctor asked Mokuba as he watched Noah race off up the steps, and then turned to see Mokuba racing down them.

Mokuba continued across the empty space without the Doctor and was first back to the TARDIS. He hadn't expected to see either of the two step-relatives and now longed to be back with his brother even more. The TARDIS door refused to open from his touch but willingly did so for the Doctor's as he held it open for the boy to enter and frowned. "Want to explain to me what those tears are for?"

_Tears_? Mokuba brought his hand up to his face and felt the droplets trickle from his eyes. He'd been trying to hold them back as he now saw the similarities between his two brothers; both of them forced by Gozaburo to leave their childhoods behind, and both of them he wanted to see smile again "Noah's dead." Mokuba began to explain. "Seto wouldn't let me bring him back, and I know you won't allow me to either."

The Doctor watched as Mokuba's mouth trembled and then the boy began to sob. It was heart braking seeing the boy cry in front of him and knew the helpless feeling that Mokuba was experiencing as he was learning that he wasn't allowed to intervene with history and save the step-brother too. "Good boy." He cooed as he pulled Mokuba closer to him and let the boy cry against him for as long as he needed to. "It gets easier over time." He lied as he hadn't yet managed to convince himself of the same thing over all his years of time travelling.

"Sorry about that." Mokuba apologised once he had stopped crying and broke away from the Doctor's embrace. He felt silly for being so emotional; maybe he should toughen up a little like his brother.

"No worries." The Doctor smiled. "Why don't you go and set our destination forward five years whilst I recharge my sonic?"

Mokuba nodded and they both approached the controls at the centre of the TARDIS where he began to enter the details and the Doctor carried on around opposite him to place the metallic device into a slot for recharging. The lever was pulled and the TARDIS shook as it began to move through time, but the shaking increased until an explosion from within the control's core sent both passengers flying backwards and the TARDIS into darkness.


	4. Chapter 4

**Once again, thank you for the reviews. :)**

**I hope none of you are disappointed with where this is leading.**

**Chapter Four**

His vision was extremely blurry as Mokuba opened his eyes and tried to focus on the room he was in. Slowly the images sharpened and he could now make out the smouldering controls of the TARDIS in the flickering light from above. Looking to his right he saw the Doctor as he lay unconscious and raced over to check that he was okay. "Wake up." He shook the Doctor gently.

"Rose?" the Doctor mumbled groggily as he struggled to open his eyes and then squinted trying to bring the dark haired boy into focus, a puzzled look appeared on his face. "I've just realised, I don't know your name yet." He hoped the boy wouldn't question him further about the name he had mumbled.

"Mokuba." He sighed, relieved that the Doctor was conscious again and helped the time-lord sit up. "What happened?"

"The TARDIS must have shorted out one of her circuits when I recharged the sonic." The Doctor got to his feet and headed over to the controls to see what kind of damaged had been caused. "Unfortunately the old girl tends to play up every now and then, usually at the worst possible times." He typed away at the keyboard and an image flashed on the screen. "Looks like the Zeiton supply has been cut off, but we'll soon have that fixed."

Taking the sonic screwdriver from the recharging port he checked to see if it had charged before his time machine had malfunctioned. A bright blue spark shot out across the room which had more charge than previously. "That's better." the Doctor smiled now that his device was working properly again.

"Are you sure that won't kill anyone?" Mokuba asked as he jumped in surprise from seeing the powerful blast.

"Positive." The Doctor said as he crouched down to be able to crawl underneath the control desk to find the burst tube in the Zeiton supply. He lay on his back as though he was simply fixing the undercarriage of a car and fought his way passed the wires he had been unable to fix for the TARDIS' chameleon circuit which was the reason it had remained as a nineteen fifty's London police call box since that had been the last form it had taken shape of before they broke.

"Aren't you able to get a new time machine if this one is so unreliable?" Mokuba asked curiously. "Or did you build it yourself?"

The Doctor laughed. "You don't _build _a TARDIS; they're grown and bonded with their Time-lord on Gallifrey." The laugh faded at the mention of his home world and he was glad that the boy couldn't see him at that moment. He continued to search through the wires, with no desire to talk more about his planet or mention the fact that he had taken his TARDIS unlawfully.

"So you're an alien?!" Mokuba exclaimed in surprise.

"Only half, my mother was human." The Doctor replied glad that Mokuba hadn't asked him more about his home world.

A happy smile appeared on Mokuba's face, yet something else which his brother had been wrong about. The many things he believed in which his brother didn't were turning out to be true making his world just that little bit brighter and happier, and not as dull as Kaiba had tried to make it seem. The thought of another planet excited him and he wanted to know more as he bombarded the Doctor with questions. "Where is Gallifrey? What's it look like? How many species of alien live there? Can you take me some time?"

Letting out a heavy sigh, the Doctor decided that he'd tell Mokuba the basic facts which he hoped would stop him from asking anymore. "My planet no longer exists; it was destroyed during the Last Great Time-war." He felt his hearts ache; "I'm the last of my people."

Mokuba's excitement vanished instantly at hearing the Doctor's words and he thought back to the way he had acted after hearing that his brother was dead. In his anger he'd turned on the Doctor and called him a liar for not knowing how he felt when in fact the Doctor had witnessed losing a lot more than just his family. "I'm sorry, for the way I behaved." Mokuba said sadly.

"No need to apologise, you didn't know." The Doctor replied as he pointed his device at the tube he thought that needed repairing, but still there was no change to the TARDIS' state.

There was now silence between the two of them. Mokuba could sense that the Doctor had become uncomfortable talking about his past, he'd experienced his brother close up often enough, so knew that what he was about to ask would probably be pushing his luck but he had to know; "Weren't you tempted to go back and intervene with history?"

The Doctor found it hard to draw breath as memories that were hundreds of years old raced through his mind as clear as if they had happened only hours ago. He had been foolish enough to try and alter his planet's history only to make things worse and uncover truths he wished would have remained hidden from him. There was also the revenge he had taken against the species know as the Daleks whom he had chased down and practically wiped out in return for the murder of his people, something he wasn't proud of and even regretted more than he thought possible. "I did." He said finally. "I don't wish to talk about the subject anymore, so please don't question me about it."

Silence fell on them once more as the Doctor continued working and Mokuba thought out loud about the name he had heard earlier. "Who's Rose?"

The sonic screwdriver fell from the Doctor's hand at the mention of her name. _Rose. _Again he felt it difficult to breathe as he remembered her slip away from him as he watched her dragged into the void he had opened to swallow up the warring Daleks and Cybermen in order to save the human race, and then sealed her in a parallel universe, never to be seen again. _Please forgive me._ "She was an assistant and very good friend of mine who is no longer with us." He explained and carried on working once more.

Mokuba thought about how horrible it must have been for the Doctor to lose even more people around him. "Did you love her?" he asked.

"What kind of question is that?" The Doctor laughed nervously masking his true feelings and was glad that Mokuba couldn't see him redden in the checks at the mention of the question. "Enough about me, what about you? Tell me about yourself." The Doctor had to stop the boy from asking him more questions that he didn't want to answer.

"There's not much to tell." Mokuba shrugged. "It's just me and Seto, that's the way it's always been for as long as I can remember. Life's pretty good, as Seto made sure it would be for us, even though he's not the same brother that I remember from when we were younger."

"Why's that?" the Doctor tried to keep the boy talking for a little longer as he was near finished mending the Zeiton supply.

"We were orphaned at a young age and once our step-father adopted us, that's when he changed." Mokuba was beginning to feel uncomfortable and knew that the Doctor must have felt the same a short while earlier. "He loves me, I know he does, he'd do anything for me, but he doesn't show it openly anymore. He never talks to me about how he's feeling and I'd give anything just to see him smile again like he did before that time."

There was a whirling sound that filled the room as the Zeiton supply was completely reconnected and the TARDIS continued to the chosen destination. The Doctor got up from underneath the control desk and wiped his slightly grubby hands on his trousers. "Just give him time and he'll learn to smile again, despite what it is that may be haunting him." The Doctor flashed Mokuba a wink and a smile. "Trust me."

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They had entered the building, gotten passed security and where now on their way down to the hidden room below the KC building's basement. The doors opened and Mokuba followed behind the Doctor, this time making sure to stay as far away as possible from the conveyor belts of the conversion chamber.

Now that the Doctor knew where the main controls were, and with his sonic screwdriver recharged even more powerful than before, it didn't take more than a matter of seconds to make sure that the machine would remain unusable from then on.

"I just need to check the systems here for any information relating to this machine and then I'll drop you back in your time again." The Doctor explained fixing back the control panel as they rode the elevator up to the top of the building.

"Seto." Mokuba smiled happily, glad that this nightmare would be ending shortly and that he'd be reunited with his brother again. He was also sad that his time with the Doctor would soon be ending too and wondered if he'd be okay travelling through time on his own once more. "You'd be welcome to stay and spend as much time as you'd like with me and my brother."

"Thank you." The Doctor smiled grateful for the kind offer. "I'll keep that in mind, but for now I still have a lot of travelling to do." He saw the boy look disappointed with his reply. "Maybe our paths will cross again, though I may be a different man the next time we meet."

Together they left the elevator and Mokuba carefully led the Doctor around to Gozaburo's office were the main computer system had been stored when he had control of the company before Kaiba. The room which was Gozaburo's office would later become a gym for Kaiba Corp's employees, a place that Kaiba would never step foot. It was over twice the size of the room that Kaiba would chose for his office and apart from the fact that their step-father had fallen from the window in that room, Mokuba wondered why his brother had changed it. Probably for that very reason as he was tired of being accused for the old man's death, so Mokuba couldn't blame him for that.

Luckily the office was empty as Gozaburo was currently attending a press conference along with his eldest step-son, as a big announcement was about to be made but Mokuba couldn't quite remember what. It didn't matter to them though as it gave the Doctor the time he needed to search the computer systems for the information he was looking for. "Gotcha!" he shouted happily as the plans for the conversion chamber were displayed and trademark with the Cybus Industries logo. "How'd he get his hands on that?"

"What?" Mokuba asked curiously at the surprised look on the doctor's face.

"Cybus Industries, it's ……." The Doctor began to explain but heard voices outside of the room. "Quick hide." He hissed to Mokuba and indicated to the boy to go round behind a huge screen that ran along most of the room to almost separate it into two. He quickly shut the computer system down so that no trace of their presence would be left behind and then joined Mokuba as they quietly waited behind the dividing screen.


	5. Chapter 5

**Another big thank you for the reviews :)**

**Chapter Five**

From behind the screen Mokuba and the Doctor watched as the door to the office opened and in stepped Gozaburo making his way closer to them as he headed for his desk. The door had almost closed when the eldest of the two Kaiba brothers entered making sure that it closed properly behind him.

Mokuba almost gasped at seeing his brother as he peered through the tiny holes in the dividing screen and held his hand across his mouth hoping that he hadn't made a sound to give themselves away in their hiding place. He glanced at the Doctor who was busy watching the two Kaibas and turned his own attention back to them as well.

"What's wrong Seto?" Gozaburo laughed for his own amusement as he saw his step-son come storming towards him baring an angry look. "Your face has been looking like that for the past hour."

"You screwed me over." Seto hissed, his face full of hatred for his step-father.

"Don't I always?" Gozaburo laughed evilly and saw more anger burn in the blue eyes fixed upon him. "Your attempt to takeover my company has failed miserably."

Thinking back, Mokuba remembered the time that his brother had started to turn cold towards him as he had focused on buying up as many of Kaiba Corp's shares as possible to gain full control over the company. Seto had succeeded in gaining forty-nine percent of the shares whilst Gozaburo also had forty-nine percent, the last two percent had belonged to himself which he willingly gave to his brother, guaranteeing him control, so how could the attempt have failed?

"You may have the majority of shares for my company but thanks to the clause I made in the contract you signed months ago, you aren't able to take it from me until your eighteenth birthday." He told his step-son the fact which he had recently learnt about in front of the press and had remained helpless to strike back there and then. Leaning back in his chair, a satisfied smile crossed Gozaburo's face at being one step ahead of the opposition. "A lot can happen over the next four years until that time comes, and when it does you won't have a single share of _my_ company to your name." he watch as the anger began to subside as tiny traces of helplessness crept into the boy's eyes and relished every moment of it. "Did you honestly think that I'd place all of my trust into that bastard runt brother of yours when I knew where his loyalties would lie?"

The old man had hit a nerve when he spoke about Mokuba causing his step-son to spit in his face. Seto knew that he'd have to face the consequences but no one spoke about his brother in such a tone. "If you _ever_ refer to Mokuba like that again I'll……."

"You'll what?!" Gozaburo roared as he struck out and knocked Seto down to the floor for the action he had made, reminding the boy which of them it was whom held the power over who.

Mokuba fidgeted at the sight of seeing his brother being hit and then felt the rage build up inside him as he clenched his fists tightly and was held back by the Doctor who feared that the boy may do something foolish. The feeling slowly eased and the two continued to watch as Seto put a hand to the bleeding wound on the side of his face and smirked as he stared at his blood covered fingers. "What do you think the press will make of this? It doesn't exactly fit in with the perfect father and son image that they have of the two of us."

"You know what will happen if you speak out about any of this." Gozaburo warned Seto who sat at his feet on the floor. He couldn't believe that he'd been so easily provoked into the attack and wiped the spit from his face.

Seto kept firm control over his emotions; he couldn't risk his step-father knowing how he was truly feeling, though he knew that his eyes gave away his sorrow but just how much he wasn't sure. Gozaburo knew that whatever abuse or punishment he gave him that the boy would take it, as he seemed to of stopped caring about himself a long time ago, but if it was instead directed towards Mokuba then it would hurt the elder brother every single time and even more so. Seto hated himself for letting the old man know his weakness, but he wasn't prepared to let his brother get hurt in any way, especially if Gozaburo chose to ……. he didn't even want to think about it as he would never forgive himself if Mokuba was to suffer the same abuse that he had to endure.

"I'll make you a deal." Seto said as he used the crisp white sleeve of his shirt to wipe away the dark crimson blood from his cheek. Using his back-fired takeover attempt he'd come up with another way to turn it around to his favour and escape from his step-father. "I'll give you my percentage of the company if you take my brother and I back to the orphanage."

Mokuba's jaw dropped. That didn't sound like something his brother would say, he'd always hated the place where they had been left by their relatives who abandoned them all those years ago. Something must have been extremely wrong for his brother to want to go back, as he'd already fought so hard to get them away from that place.

"That way, you'll have full control of Kaiba Corp _and_ you'll be rid of me and Mokuba for good." Seto prayed his plan would work, it had to, he had nothing else left to play down. "Things will be back to just the way you like them."

As tempting and true that Seto's deal was, Gozaburo wasn't going to accept. He could easily regain full ownership of his company, and as much as he'd loathed the fact that he had been scammed into adopting both boys he'd gotten use to having them around, especially the pleasure he got from bending the eldest brother's will. "You'd like that wouldn't you?" he smirked and watched the boy fight to keep his face calm and eyes from overflowing with the moisture that was building up in them.

"What do you want from me?" Seto's voice shook even though he had meant for it to sound demanding, as he struggled to hold back the heartache of not being able to free himself from the nightmare which he had trapped himself in ever since the day he had challenged the old man into playing the chess game at the orphanage. He summoned as much strength as he could and stood back up on his feet again.

Gozaburo just stared at the boy before him. He'd gotten his revenge for the embarrassment of losing the chess game many times over and now just simply enjoyed causing him to suffer. It was clear to him that Seto was almost at breaking point; soon the boy would either give up all hope and end his life or unleash the trauma which had been built up in a fit of rage. Whichever it was to be he was looking forward to witnessing it, even if he was to be on the receiving end of an all-out assault, but from the way the boy looked right now he suspected that he'd lose hope and crumble.

The big blue eyes that stared out from Seto's face looked as though they were about to explode showers of tears any moment now. Mokuba couldn't ever recall seeing his brother cry at any point in his life. He had always been so strong and coped with everything life had thrown him, so what was it that was making him act like he was now? Leaning closer to the screen he knocked it slightly causing it to move the tinniest amount.

"Leave my office, now." Gozaburo suddenly demanded his step-son who refused to move after he had been told to do so, proving that he still had some fight left in him.

"Not until you answer me." Seto's voice was sounding firmer as he continued to stand his ground.

"Leave immediately!"

"No."

"Fine." Gozaburo calmed his voice, glad that there was still some spirit left in the boy for him to break. "We'll have Mokuba join in our fun tonight." He glared into the terrified blue eyes. "You can watch while I take his innocence, or better still, I'll make you take it from him." His lips curled in a twisted smile as he saw Seto back away to the door at the very mention of sexually abusing the younger brother too.

_What did he mean by that?_ Mokuba thought to himself. His brother seemed to have backed down awfully quickly from whatever bluff made by the old man. His eyes widened as he caught on to what had been happening between the two of them. _No, Seto wouldn't stand for it, there's no way he'd of let our step-father use him like that, not unless….._ He stopped in his thoughts as he watched his brother open the door to leave and felt the silent tears slide down his face. _He let him, because of me._

Seto stood in the doorway ready to leave, gave one last look at his step-father and felt extremely sickened by the old man's threat. He would do whatever it took to keep his brother safe from the sexual abuse he hated so much even if he couldn't save himself. Closing his eyes caused the water to fall from them in one big heavy gush and Seto wasn't bothered if Gozaburo saw the tears fall as it would be the very last time he'd ever let himself be overcome with such painful emotions that portrayed his weakness. Only anger and hatred remained in his eyes when they reopened, these would be the only two emotions he would feel from then on. Silently he promised himself that he'd knock his step-father down the power ladder the next time they'd meet and then _Kaiba_ stepped out of the room.

The door to Gozaburo's office closed and the old man turned to face the screen he had seen move only moments ago. "I know you're behind there so show yourself." He demanded.

Both faces showed signs of shock as Mokuba and the Doctor stared at each other in surprise. 'Stay here' the Doctor mouthed silently to Mokuba's tear stained face. He'd had to get himself out of many tight situations before and just hoped that the upset boy would be able to stay strong until he could get them both out of this one. "Hello." The Doctor said cheerily as he revealed himself from behind the screen.

"You." Gozaburo said in a despising tone as the man's face was familiar to him but he couldn't quite remember where from. "What are you doing in my office?"

"Waiting to be able to talk to you actually." The Doctor smirked as he placed his hands into his trouser pockets. "Tell me what you know about Cybus Industries, and the conversion chamber hiding below your building."

Gozaburo's eyes narrowed dangerously on the intruder who knew details which he hadn't shared with anyone else. "Who are you?"

"Someone you don't want to make angry." All of the Doctor's cheery disposition drained away as he stared back just as threateningly as the look he was receiving, something which was made easier for him to do after the way he'd just seen the old man treat the younger Kaiba.

Mokuba peered out from his hiding place and watched the conflict between the two men as he wiped away the last of the tears from his face and wished that there was something he could do to help right now as he felt so useless. He fought hard to keep back the surge of tears that rebuilt as he thought about what he had just leant of the abuse which his brother had had to endure from their step-father. For a brief moment he wished that the truth which had been hidden from him still remained that way but then changed his mind as he now knew just what an evil monster Gozaburo was and had a better understanding of why his brother hated him so much. As he gripped at his locket sad and happy tears mixed together as he now truly appreciated the sacrifices that his brother had made for him.

"Do you have any idea who you're dealing with?" Gozaburo hissed threateningly.

"A sicko who gets a kick out of abusing young boys?" He would stand off against the old man all day if he had to, but the Doctor wanted to get the information he needed and leave. "Now tell me what I want to know."

"I'm having you removed from my building." Gozaburo barked not wanting to answer the Doctor's questions and reached for the intercom on his desk to call for security only to see it burst apart in a blue flash of light. He turned to see the origin of the blue light and saw the brown coated man holding a small silver cylinder in his hand. The device to him was an unknown weapon of some sorts, and he didn't fancy seeing just how long it would be before the stranger turned it on him or what damage it would possibly cause. "Lumic and I go way back." He began to explain and quickly glancing at the bottom left draw of his desk, he wondered if he'd be able to distract the man long enough to be able to retrieve and draw his gun on him.

Satisfied that he was getting the facts he wanted to know, the Doctor lowered his sonic screwdriver. John Lumic had been the founder of Cybus Industries whom he had met during his time in the parallel universe so it was likely that his counterpart in this one also knew the exact same information for the conversion chamber.

"Together we worked on creating the ultimate being." Gozaburo elaborated. "He had the knowledge needed to come up with the body whilst I worked on the computer programme that would transfer the data of a human into the mechanical mind of the host. Only he changed his mind during the process and instead wanted to use our combined creation to prolong human life, when we had both originally agreed that it was to be a weapon of war. The design was changed so that the human brain would be sustained in a cradle of chemicals connecting the impulses to the exoskeleton so my efforts became useless in the project which I then took over myself."

"And what of Lumic?" the Doctor asked as he'd also need to make sure that no trace of the chambers details remained behind with the creator. Lumic's intentions may have been for a good cause but the final result of the conversion only produced emotionless killing machines and the Doctor couldn't let anymore be reproduced anywhere in time nor space.

"Despite being an old friend of mine, he faced the same fate as any other of my oppositions and was squashed." The twisted smile that had been seen earlier reappeared on Gozaburo's face. "I personally put an end to that miserable life of his that he wanted to extend."

"You murdered your friend?!" the Doctor exclaimed in disbelief but at least he now knew that he didn't have to worry about tracking anyone else down to bring an end to the whole thing, and just had to return the boy back to his proper time.

Mokuba listened as memories and images of his brother raced through his head, ones where he resembled their step-father a little too much. Since the very first time he had lost the duel to Yugi, Kaiba had been out to seek revenge against him including trapping his opponent and their friends on an island about to be blown up which would have probably killed them all had they not been able to escape on the medical chopper at the last moment before the explosion. Looking back now, he knew it was no accident like his brother had told him and that Kaiba had himself become trapped in the vicious circle of were the abused had become the abuser. Anger built up inside him as he hated his step-father for altering the kind loving big brother he had once known and in his place was an almost clone of Gozaburo himself. And yet here he was hiding and not doing a single thing to fight and try to save the brother who had given up so much for him.

Without thinking what he was doing, Mokuba let his anger control him and felt himself break out into a fast pace as he emerged from behind the screen and ran to the Doctor's side. He snatched the sonic screwdriver from the time-lord's hand and approached his step-father with it raised and ready for use. "I'll make you pay for what you've done to Seto!" he screamed as he forced the glowing device against Gozaburo's neck startling the old man to fall back into the chair behind him.

"Mokuba." The Doctor said disapprovingly as he watched the boy who had finally had enough of feeling helpless all of the time. He wasn't worried too much as he knew that if the boy was to use the weapon he held that he wouldn't be able to 'seriously' damage or kill the step-father, but he did feel disappointed that the boy had let his emotions get the better of him. Hopefully Mokuba would see sense in what was happening and back down from his interference, but the boy's inner battle was something that he himself had no control over so all he could do now was wait and watch.

"Mokie?" Gozaburo's voice was weak from the fear of the unknown weapon pressed tightly against him and from the surprise of seeing what looked like his youngest step-son, only not as he had ever imagined him as this boy wasn't the same young, sweet, innocent and weaker one he had seen earlier that morning.

"Don't you dare call me that." Mokuba hissed and shook as he fought back the urge to blast his step-father and cause him as much pain as possible. He wasn't sure if it would benefit his brother in anyway but it would make him feel better knowing that he had done so, and Gozaburo would deserve whatever it was that he got. _I mustn't interfere_ He told himself as he remembered what the Doctor had told him back in the TARDIS.

"Surely you wouldn't hurt me now would you?" the old man smiled at the boy who was hesitating and clearly didn't have what it took to carry out his threat yet the metallic device was still forced even more into his neck.

_Just do it, make him pay for everything he's done to your brother._ Mokuba heard a voice inside his head urge him on and as much as he'd like to follow through with his attack he just couldn't do it. Not only would he be interfering with history but if he were to press the button right now and inflict pain upon the defenceless man then would that really make him any better than his step-father? Had it been the old man's intention all along to create monsters out of both his brother and himself? Were they just another one of his destructive creations?

Slowly Mokuba pulled back the sonic screwdriver from his step-father's throat as he knew that the time the old man had left was short as he'd soon meet his end, Seto would make sure of that. He hated to admit to himself but he now believed that Gozaburo's death was no suicide and that his brother must have killed him after being pushed too far for one last time, and now he understood why. "You'll get what you deserve when the time comes." He told him as he backed away and then turned to walk back to the Doctor.

A proud smiled bore across the Doctor's face as he saw the boy returning to him after being able to resist against the emotions that had nearly driven him into doing something he'd deeply regret later on. He watched Mokuba smile back and saw something different about the boy, as he had become a stronger person whether he realised it or not, and then paying attention to what was happening over Mokuba shoulder's he called out. "Behind you!"

Mokuba spun around from the Doctor's warning, saw Gozaburo now holding a gun towards him and without a second thought raised the device in his hand and pressed the button. A powerful blue blast erupted from the end of the sonic screwdriver and hit the old man before he had the chance to pull the trigger of his gun which dropped to the floor. The blast was so strong that it knocked Gozaburo back into the chair where he'd been seconds ago causing it to wheel speedily across the office floor and crashed into the window which shattered as the weight of the old man's body carried him through to fall to his death down on the empty court space bellow. Wide eyed and feeling shaken by what he had just seen, Mokuba staggered backwards and felt the Doctor steady him to regain his balance. He released the grip on the sonic screwdriver as the time-lord took it back from him.

"Looks like we just made an even bigger mess of things." The Doctor sighed as he looked straight onwards out of the broken window. He knew that it had been an unavoidable accident but still it would change the future of things from then on.

"No." Mokuba spoke as he looked at he calendar on his step-father's desk to see that the date matched that of Gozaburo's death. "It's supposed to happen this way." Mokuba stared into the space in front of him as he tried to come to terms with what he'd just seen. He'd been right a moment ago when he decided that his step-father's death was no suicide, and now he felt guilty about having suspected his brother of murder as he finally knew the truth. "I killed him."


	6. Chapter 6

**Thank you for the reviews :) **

**Chapter Six**

Leaving the building as quickly as possible the Doctor and Mokuba made their way back to the TARDIS with neither of them stopping to look behind at the growing crowd that gathered outside the KC building. Both of them remained silent as they quickly walked beside each other across the court yard and entered the blue phone box, Mokuba first followed by the Doctor, who saw the other Kaiba brother held by several security guards, as he closed the TARDIS' doors behind him.

"Are you sure you're okay?" the Doctor asked as he approached Mokuba and rest a comforting hand on the boy's shoulder who stood at the controls already entering the next date into the system.

Mokuba nodded as he bit hard onto his lip and thought about what he had done. Although he had been responsible for Gozaburo's death, it wasn't that which plagued his mind but the fact that his brother had suffered so much because of him which he had been oblivious to the whole time and that he himself had caused him to suffer even more with the old man's death as Kaiba would be the one that fingers were pointed at with the murder accusations since he had been the last person to 'officially' see Gozaburo alive. He looked up at the Doctor and forced a weak smile to show that he'd be okay.

"You mustn't blame yourself." The Doctor frowned, not buying the boy's smile and completely unaware as to what Mokuba was really thinking about. "It was an accident." He pulled the lever and the TARDIS transported them back to nearer the present time.

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Sitting alone in Kaiba's office, Mokuba counted down the minutes and seconds to when he would be able to see his brother again. The past several hours had seemed like a lifetime to him and he was anxious to make sure that things were back to how they were before he'd first meet the Doctor. He sat there looking out the window and ran through the plan of action that they had come up with.

They'd entered the building shortly before the Doctor had arrived there first time around and managed to go unnoticed by the receptionist who was busy checking the IDs of several other people at once. Mokuba was to wait in the office for his brother to return from the research lab so that he didn't run into his other self. The Doctor was going to leave his other self a reminder of the things that were going on and one of them would take the Mokuba from the lab to the TARDIS to explain things. Concerned that they had created a time paradox and that there would then be two of him, Mokuba voiced this to the Doctor who confused him even more talking about 'wibbley-wobbley, timey-wimey.' But assured that all would be okay.

With his back to the door Mokuba jumped in the huge black chair he sat in as he heard the door open and footsteps coming closer to him. Excitedly he spun it around on its pivot to turn and face Kaiba who froze were he stood with a surprised and puzzled look on his face. "Mokuba?"

"Seto!" Mokuba cried happily as he leaped from the chair and raced towards his brother unable to stop the tears from rolling down his face.

"Why aren't you in the lab watching over that impostor?" Kaiba demanded to know as his brother wrapped his arms around him tightly. There was no reply as Mokuba began to sob. "Mokie?" Kaiba's tone was softened.

"I missed you so much." Mokuba wept with his head buried in the folds of Kaiba's flowing white coat, knowing that his brother would never understand what he had just been through since he was unable to open his mind to the facts and possibilities of such things as time travel.

"It's only been a couple of minutes." Kaiba stated as he looked down at Mokuba's dark scruffy hair and wondered what it was he had done to upset his brother this time.

"It felt like a lot longer." Mokuba smiled as he brushed away the tears and stood listening to his brother's heartbeat which drowned out the horrible memories of the cold emotionless Cyberman that had tried to harm him.

The fact that there was a stranger in his research lab left Kaiba's mind as he focused all his attention to his younger brother whom he continued to let hug him tightly for awhile where they stood in the middle of the room. He hated seeing Mokuba upset and felt next to useless when it came to comforting him as he'd lost touch of how to be sympathetic towards others over the years. For a moment he hesitated before he softly patted his brother on the head with one hand and shoulder with the other but stopped shortly after as he thought he heard Mokuba's voice outside his office.

"Hold on a minute." Kaiba said as he gently broke away from his brother so that he could investigate the noise coming from the corridor.

"No." Mokuba yelled as he grabbed hold of his brother's arm before Kaiba had the chance of opening the door. "Don't leave me." He pleaded with big watery eyes as he couldn't let his brother interfere with the plan and risk losing him all over again.

"Okay." Kaiba nodded after some slight hesitation as Mokuba coiled around him again and let go of the door handle. He had no idea what it was that had upset his brother but it was clear to him that Mokuba needed him here and now, and wasn't going to let him down like he had done so much of over the past years. Taking his cell phone from his inside coat pocket he speed dialled his secretary's number. "Cancel _all_ of today's appointments and meetings, something's come up which is much more important." He hung up after his order and turned his attention back to Mokuba who was squeezing him again. "What's wrong kiddo?"

"Nothing." Mokuba mumbled and then thought about asking his brother to talk about the past whilst he seemed to have his full attention for once, but then decided against it as he didn't want his brother to close up and change moods right now. "I guess I just never truly appreciated you until just recently."

_That's it?!_ Kaiba kept his thoughts to himself for fear that he may upset his brother even more as Mokuba was over emotional enough as it was and didn't want to start him crying again. He also felt slightly guilty himself as he never actually expressed just how much he appreciated his brother either. Maybe now was the time for doing so?

"I'm sorry." Mokuba blurted out as Kaiba was about to attempt to say something.

"For what?" Kaiba asked as he wondered just what it was his brother might have done for him to apologise willingly.

"For making you weak." Mokuba whispered thinking about what he had witnessed back in his step-father's office.

A sigh escaped Kaiba as he knew he'd always fail to understand what went on underneath the mass of black scruffy hair which he stared down at. Now placing both hands on his shoulder's Kaiba gently pushed Mokuba back from him so that he could drop down to be more level with his little brother. "Yes it's true, you are my weakness, anyone can see that." He looked deep into the grey-blue eyes and couldn't recall the last time he'd felt so close to the one who meant so much to him. "But you're also my strength."

Mokuba's eyes began to fill up again as he heard his brother's words. "Really?"

"Really." Kaiba nodded. "There are a million things which I wouldn't have been able to overcome if you hadn't have been there for me when I needed the support to keep me going from one day to the next." He felt his lips dry out as he hesitated and wet them again before he continued. "I'm the one who should be apologising for not letting you know how much that I appreciate you for standing by my all this time. I've done many things that I'm not proud of, and you've never once turned away from me." His gaze was reflected back in his brother's watery eyes as though it was a mirror and he struggled to stop his voice from shaking as he spoke. "I just wish that I could be the brother that you truly deserve."

"You're more than I deserve." Mokuba said happily as he wrapped his arms around his brother's neck and let the tears flow freely as he felt Kaiba's arms wrap around him. It had been almost forever that he'd dreamt for this day to come and all of the last few hours, even years, seemed to disappear as the brother he had once known was returned to him.

The soft black hair of his brother began to feel damp against his cheek and Kaiba knew it was time to brighten the mood. "So now that we have the whole day to ourselves, what would you like to do?" He eased his brother from him and helped to dry the rest of the younger boy's tears. "Anything at all, your choice."

Mokuba thought hard. "Can we watch a film?"

Kaiba nodded.

"A trilogy perhaps?"

_Oh no. _Kaiba knew that his brother was going to choose the Back to the Future films, but if that's what Mokuba wanted then so be it. "You do realise that I'll probably complain about the whole aspect of time travel throughout all three?"

"I wouldn't have it any other way." Mokuba laughed and saw his brother laugh too.

"You're weird." Kaiba ruffled up the younger boy's hair and rose to his full height.

"One of us has to be." Mokuba smiled up at his brother and remembered the Doctor's words. _'Just give him time and he'll learn to smile again…….Trust me.'_

_END_

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**Well this adventure has come to an end :(  
**

**I hope you all enjoyed it, and again 'thank you' to everyone who left reviews which kept me motivated to regularly update.**

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Kaiba: What kind of crap do you intend to put me through in your next fic:? (scans the first two completed chapters and groans) I _hate_ you!

KG: I know.

_Next fic coming 1 July._


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